I have three favorite books so here they are :
My favorite are "Suicide" by Emile DURKHEIM. It's a sociology book about causes of suicide, and who show that people who commit suicide aren't always weak people.
The other one is "La grande déculturation" from Renaud CAMUS, who show how, by trying to make culture accessible to everyone, governments make people more and more uncultivated. Quantity > Quality
And the last one is from Renaud CAMUS, and is named "Le grand remplacement". This one show how North European culture is being replaced because of legal and illegal migrations, because of accepting that communities with differents cultures/traditions... can keep their traditions while living in others countries...
So here's my favorite books, I can't really choose between them.